I did some research into the inks that my tattoo artist uses and found that one of the three brands of ink he uses is vegan: Starbrite. I am now happy in the knowledge that my January tattoo will be vegan!
Oh, you probably want to know why most inks aren't vegan. The liquid that the ink is suspended in (the transport mechanism) is often animal based glycerin rather than vegetable based. Some inks use crushed insects to get color, and some use bone char.